The effects of dietary trilinoelaidin on fatty acid and acyl desaturases in rat liver.
The effects of incremental amounts of dietary t,t-18:2 on liver microsomal delta 5 and delta 6 acyl desaturase activities were studied. The hepatic concentration of t,t-18:2 increased linearly from 0 to 1.6 mg/g liver as dietary t,t-18:2 was increased from 0--50% of dietary fat. This apparently inhibited the conversion of linoleic to arachidonic acid in liver tissue because linoleic acid increased from 1.2 to 3.1 mg/g liver, while arachidonic acid concurrently decreased from 3.9 to 1.9 mg/g liver tissue. This reflected the inhibition of delta 6 desaturase by t,t-18:2. The delta 6 desaturase activity in liver microsomes of rats fed 10, 20, and 50% of t,t-18:2 in their dietary lipids was 97, 75, and 51% of the activity of rats fed no t,t-18:2. In vitro tests showed that t,t-18:2 specifically inhibited liver delta 6 desaturase. The delta 5 desaturase activities did not increase significantly as dietary t,t-18:2 levels increased. This study showed that dietary t,t-18:2 by depressing delta 6 desaturase activity may affect essential fatty acid metabolism.
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism; D000090943:Delta-5 Fatty Acid Desaturase; D044943:Fatty Acid Desaturases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D050602:Linoleoyl-CoA Desaturase; D008099:Liver / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000494:pharmacology*
D001095:Arachidonic Acids; D000090943:Delta-5 Fatty Acid Desaturase; D005227:Fatty Acids; D005231:Fatty Acids, Unsaturated; D008041:Linoleic Acids; D014280:Triglycerides; D016718:Arachidonic Acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase; C009564:trilinolein